Wells L L, Lowry V K, DeLoach J R, Kogut M H
Texas A&M University, College of Veterinary Medicine, College Station 77843, USA.
Dev Comp Immunol. 1998 Jan-Feb;22(1):103-9. doi: 10.1016/s0145-305x(97)00024-4.
Chicks are most susceptible to Salmonella infection during the first 4 days post-hatch. In poultry, one of the primary cells in the innate immune response to early bacterial invasion by Salmonella is the heterophil. Previous studies using a granulocytopenic chicken model in more mature birds demonstrated the significant role heterophils have in the defense mechanism against Salmonella. In the past studies have also shown the efficiency of heterophils from 3- to 5-week-old chickens to phagocytose and kill Salmonella as compared to monocytes. During the present study, we investigated the phagocytic and bactericidal activities of heterophils from chickens during the first 7 days post-hatch to evaluate whether decreased heterophil function plays a role in the susceptibility of young chicks to Salmonella infections. Peripheral blood counts demonstrated no differences in the percentages of heterophils during the first week post-hatch. The phagocytic index of the heterophil did not change on day 1 or day 4, but doubled by day 7 (day 1, 30.69; day 4, 33.99; day 7, 60.46). Interestingly, the bactericidal activity of the heterophils from all three age groups efficiently killed Salmonella enteritidis. Based on this data, we conclude that a relationship exists between the age of the chick, the functional activity of the heterophil, and the susceptibility to organ invasion by Salmonella.
雏鸡在孵化后的头4天对沙门氏菌感染最为敏感。在家禽中，对沙门氏菌早期细菌入侵的先天性免疫反应中的主要细胞之一是异嗜性粒细胞。以往使用粒细胞减少的鸡模型对更成熟鸟类进行的研究表明，异嗜性粒细胞在抵抗沙门氏菌的防御机制中发挥着重要作用。过去的研究还表明，与单核细胞相比，3至5周龄鸡的异嗜性粒细胞吞噬和杀死沙门氏菌的效率更高。在本研究中，我们调查了孵化后前7天雏鸡异嗜性粒细胞的吞噬和杀菌活性，以评估异嗜性粒细胞功能下降是否在雏鸡对沙门氏菌感染的易感性中起作用。外周血细胞计数显示，孵化后第一周异嗜性粒细胞的百分比没有差异。异嗜性粒细胞的吞噬指数在第1天或第4天没有变化，但在第7天增加了一倍（第1天，30.69；第4天，33.99；第7天，60.46）。有趣的是，来自所有三个年龄组的异嗜性粒细胞的杀菌活性都能有效杀死肠炎沙门氏菌。基于这些数据，我们得出结论，雏鸡的年龄、异嗜性粒细胞的功能活性与对沙门氏菌器官入侵的易感性之间存在关联。
